There has been an increase in the use of electronic relays to detect whether thresholds of specified input parameters, such as those for voltage levels, current levels, and liquid levels, are exceeded.
However, the process of troubleshooting or diagnosing a fault in a relay circuit/system is typically tedious and cumbersome due to the large number of electronic relays typically used in relay circuits.
Presently, a user needs to apply a trigger condition in order to determine whether the relay circuit/system is in working condition. That is, to check whether connectivity is working for an electronic relay to, for example, monitor overvoltage. The present method involves providing an actual overvoltage to the relay to determine whether the electronic relay is able to operate to switch states (i.e. when a predetermined threshold of a sensed input is reached), and whether the connected relay circuit/system is able to perform predetermined follow-up actions such as raising an alarm. Such types of testing may be potentially dangerous or hazardous since they may lead to power surges or accidents when providing inputs past thresholds.
Furthermore, there have been several instances when electronic relays are returned from users with “no fault found” symptoms. “No fault found” is typically known as the problem of an electronic relay circuit/system not being able to switch as it is meant to switch when a predetermined threshold of a sensed input or “fault” is reached.
For a present solid state relay, such as for a switch type connected at its input to an external relay controller (e.g. a temperature controller or a program logic controller (PLC)) and connected at its output to a circuit which the relay may be in turn controlling, an input light emitting diode (LED) indicator is typically used to indicate to a user whether the solid state relay is in a “switch to connect” or a “switch to disconnect” state. The circuit may comprise, for example, a transistor, MOSFET, thyristor, or TRIAC. The present method of checking whether a solid state relay is operating normally may only be done when the external relay controller is connected to an input of the solid state relay and the external relay controller is turned on and/or off to determine whether the switch trigger signal from turning on or off is correctly transmitted to a circuit connected at an output of the solid state relay. This form of checking may be undesirable because it may be tedious and relatively more time consuming to, for example, set up the relay controller at the input and the circuit at the output of the solid state relay.
It has been recognized that there is currently no functional test available for connectivity of an electronic relay or relay circuit/system before the electronic relay circuit/system is put into operation or usage. A user is not able to know the quality of connectivity of an electronic relay circuit/system unless the electronic relay circuit/system is put into use in an actual live circuit.
Therefore, there exists a need to provide a switching device and a method for switching states of a switching device that seek to address one or more of the problems above.